Authorities offered a first glimpse of what they say drove Benjamin Don Roden to plant the bomb late Monday at the recruiting center in suburban Tulsa.

Rejected and out of work, authorities said, the decorated former airman harbored a grudge against the Air Force, and also began blaming that military branch for blocking his attempt to join the U.S. Marines.

"He had every intention of becoming an electrician," said acting U.S. Attorney Loretta Radford. "When that didn't come to be, that's when he turned to hate."

An affidavit filed Wednesday by federal investigators documents Roden's rambling, profanity-laced letters they say he mailed to superiors, blaming the federal government for using "special warfare tactics and spying to attempt to drive these so-called inadequate performers" out of the service.

"In my case, they have also affected my ability to get a job," investigators said Roden wrote.

The documents also detail a cryptic Facebook post Roden made a day before the bomb exploded. Federal prosecutors now believe he had slashed the tires and busted the windows of a recruiter's car parked at the same center on Sunday.

"That government vehicle looks beautiful setting outside that office in (sic) tulsa," Roden posted Sunday. "That is how I am going to make up for 2 years 7 months without a job and (sic) harrassment."

A day later, the pipe bomb exploded in the Tulsa suburb of Bixby, blowing the door off the recruiting center. The building was closed at the time and no one was injured, authorities said.

When authorities arrested Roden on Tuesday, they said they searched his motorcycle and apartment and discovered a bag containing two pipe bombs, materials used to make explosive devices, a chamber-loaded .45 caliber handgun with ammunition, an AR-15 assault-style rifle, more than $3,800 in U.S. currency and an application for a German national visa, according to the affidavit.

Roden made his first appearance in federal court Wednesday, acknowledging before U.S. Magistrate Judge Frank H. McCarthy in one-word sentences that he understood the charges against him, which include using an explosive to commit a federal felony, destruction of federal property and malicious damage to federal property by use of explosive.

Roden will remain in custody at least until Friday, when McCarthy set a bond hearing. Roden's federal public defender, Whitney R. Mauldin, declined to comment on the case after the hearing. Several messages left at numbers listed for Roden's mother and sister were not immediately returned Wednesday.

Radford said the case is still being investigated and plans to submit evidence to a grand jury.

FBI agent Jessi Rice had said Tuesday that federal authorities were no longer investigating the pipe bomb as an act of domestic terrorism, and that the blast could have been the work of a disgruntled employee or a prank. But Radford refused to discount any scenario.

"While we don't believe there is evidence of domestic terrorism, we also don't want to rule out that possibility," Radford said.

The charges Roden faces belie what initially appeared to be a successful stint in the Air Force, where he was deployed and received several medals for his service.

Oklahoma Air National Guard Capt. Jennifer Proctor said Roden enlisted for Air Force active duty in April 2012 and joined the state's air national guard in October 2014.

Proctor said Roden had been a senior airman whose job involved fire protection, but that he was discharged from the air national guard's Tulsa-based 138th Fighter Wing in April. She did not provide a reason for his discharge.

Roden also received several decorations, including the Global War on Terrorism Expeditionary Medal, Proctor said. The medal is awarded to military members who have deployed overseas in direct service to the war on terror since the Sept. 11 attacks. Roden also received the Air Force Expeditionary Service Ribbon with gold border, with the border signifying that he was in a combat zone, she said.

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Associated Press researcher Rhonda Shafner in New York and writer Tim Talley in Oklahoma City contributed to this report.